Walk past the "dick tree" and the electric nipple clips and you come to The Throne, a replica of a reclining rocker that once toured the finest whorehouses in 19th-century France. An attached card says it was used for "group games."

It's here that Samuele Nubile pauses to explain what Prague's newly opened Sex Machine Museum is about.

"There are sex museums in cities all over Europe," he says. "We wanted to specialize in sex machines, to show people that this also exists."

While Berlin, Barcelona, Madrid and Amsterdam all have "museums of the erotic," Nubile insists the Sex Machine Museum is the first of its kind.

Where else, asks the museum's Turin, Italy-born manager, can you find medieval chastity belts, Victorian anti-masturbation devices and state-of-the-art S&M equipment assembled in one place?

"We want the people of Prague to like us," Nubile says. "We are adding to the culture of the city."

That's not the way some residents and city officials see it. They say the museum -- which is just off Old Town Square -- is the latest insult to the city's dignity.

Officials say there's little they can do to stem a rising tide of obscure attractions, unsavory to some, that cater to Prague's tourist hordes.

Around the corner, on Old Town Square, is the Museum of Medieval Torture Instruments, a gaudy tribute to pain that features screaming wax figures stretched on the rack. The torture displays are accompanied by an exhibition of live spiders and scorpions.

For city hall spokesman Martin Kupka, the Sex Machine Museum is a disagreeable addition to such sites.

"It's bad that these establishments are in the historical center of Prague and so close to each other," he told the daily Mlada fronta Dnes. "Foreigners might think we just leaped out of the bush."

Deputy Prague 1 Mayor Vladimir Vihan says his office tried but failed to close the Sex Machine Museum on moral grounds after receiving several complaints from residents.

"We requested the Czech police and the city business department to evaluate whether it was something that is out of line with good morals," he says. "The result was negative."

Oriano Bizzocchi, a San Marino-based entrepreneur who formerly ran a candle shop on the premises, opened the museum Jan. 1.

Because the building is privately owned and no special permits are required to open a museum, Vihan says the city's hands are tied.

"There's nothing we can do," he says. "If the owner wants to have such a museum there, he or she will have it. The city can't do anything."

The museum has already made concessions to some residents' complaints by changing its window displays.

First, Nubile moved an S&M machine that was visible from pedestrian-clogged Melantrichova Street. Still on display inside, it features leather-clad mannequins tied up in a complex system of posts and pulleys, operated by a figure in a latex nun's outfit.

Nubile says there were complaints that the machine was inappropriate for children passing by. He agrees, but urges visitors to appreciate the artistry and craftsmanship that have gone into the display.

"There are things people don't even think about, like the knots," he says. "Getting the right knots is very important. It's something we're working on."

Next, he removed two more mannequins from the windows. Dressed in latex and leather, one wore a spiked hood over its face; the other had a mask with a funnel and tube running into its mouth.

"I can understand why people protested," Nubile says. "We want to have a classy entrance."

That involves transforming the ground-level gift shop as well, Nubile says. Currently, it offers gag gifts such as giant condoms, novelty underwear and salt shakers in the shape of genitalia.

Nubile says the shop can be misleading.

"It was a quick decision to put it there," he says. "People think it's a sex shop. They come in asking for [amyl nitrate] poppers and porn; things we don't have."

Instead, he says he'll soon switch to selling tasteful erotic art, figurines and perfume.

In another effort to change the museum's image, Nubile plans to open a gallery for young local and international artists to display erotic art.

"The idea is to make an important exposition people will know about," Nubile says.

But for Deputy Mayor Vihan, the museum will always remain an eyesore.

"In my opinion such activities should not be located in the most touristy spots in the historic center," he says. "I would rather have a flower shop there, or postcards with views of Prague, something like that."